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Date: Fri, 10 Sep 2010 20:49:41 +0400
From: Solar Designer <>
Subject: Re: Attacking Windows-ALT chars in LM Hashes

On Fri, Sep 10, 2010 at 08:20:07AM +0200, Magnum, P.I. wrote:
> On 09/09/2010 10:02 PM, Solar Designer wrote:
> >Apparently, these 8-bit character codes are passed into LM hashes as-is
> >(assuming that those hashes are produced at all).
> Well, they are first converted from [in this case] cp1252 to utf-16le.
> JtR however, cheats when doing this conversion: it just puts a 0x00 
> between each char.

I think you confused LM (DES-based, 8 bits per char, two 56-bit keys)
and NTLM (MD4-based, 16 bits per char).

Your comments, above and below, probably apply to NTLM, but not to LM.

> This works for most of the charset when converting 
> from iso-8859-1 to utf-16le, but will fail on anything else. Thus, 
> without rewriting JtR you will never ever crack a LM password containing 
> a character whose utf-16le msb is not 0x00. There is no workaround.
> In this case of ALT-0xxx keyboard codes, I guess this all means that if 
> the character is the same position in iso-8859-1 as in cp1252, it will 
> work, otherwise it will not.
> This is a complex matter. I think I got it right, anyway this is the 
> gist of it.

Thank you!  Even if the original question was about LM, it is very
useful to have this info about NTLM on the list as well.


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